les verres métalliques · 2017. 4. 6. · chapter 4 in physical metallurgy, 5th edition (eds de...

Les Verres Métalliques:

— parvenus du monde vitreux

— et du monde métallique!

A. Lindsay Greer

Dept. of Materials Science & MetallurgyUniversity of Cambridge

GDR Verres, Cargèse

27–31 March 2017

• The liquid → glass

transition is kinetic

• Therefore there is a

range of glassy states

depending on cooling

rate

fast

slow

Conventionally:

• relaxation (to states of lower energy) ‒ achieved by annealing

• rejuvenation (to states of higher energy ‒ achieved by reheating to liquid

• can a wider range of states be accessed by thermomechanical processing?

• will focus on metallic glassesaccessed by mechanical processing?

Metallic Glasses

• metals and alloys are naturally crystalline

• pure metals cannot easily form glasses — their simple crystal

structures facilitate nucleation and growth

• liquid metals have a low viscosity, very similar to that of water

• alloying can stabilize the liquid, and aids glass

formation (“confusion principle”)

• for a binary alloy such as Fe80B20 (atomic %), the critical cooling

rate for glass formation is

105 to 106 K s–1

Bulk Metallic Glasses

• multicomponent compositions aid glass formation

• the critical cooling rate is low (~1 K s–1)

• glasses can be formed in bulk

(maximum diameters mm up to a few cm)

Bulk metallic glasses ― at the cutting edge of metals research

AL Greer and E Ma,

MRS Bulletin 32 (2007) 611-615.

A Takeuchi, H Kato & A Inoue

Vogel–Fulcher–Tammann plot for viscosity scaled with temperature interval between actual

and ideal glass transitions for metallic glasses in liquid and supercooled liquid states

Intermetallics 18 (2010) 406–411.

Angell plot for

metallic

glass-forming

systems

CA Angell: Science 267 (1995) 1924.

fffff

gTTg TTd

dm

))/(

log( 10

Fragility:

glassliquid

AL Greer: Metallic glasses

Chapter 4 in Physical Metallurgy,

5th edition (eds DE Laughlin & K

Hono), Elsevier, Oxford (2014), Vol.

1, pp. 305–385.

from The Times Higher Education Suppl. 3 Feb. 2006

John Desmond Bernal

1901-1971

The dense random packing model for

the structure of liquids.

Close packing of discs in 2D ―

DB Miracle, WS Sanders & ON Senkov, Philos. Mag. 83 (2003) 2409.

Interpenetrating clusters in the efficient cluster packing model of Miracle et al.

DB Miracle, Acta Mater. 54 (2006) 4317.

R Busch, J Schroers & WH Wang

Thermodynamics and kinetics of bulk metallic glass

MRS Bulletin 32 (2007) 620–623.

0

ST

G

ST

G

Elastic limit y plotted against density r for 1507 metals, alloys, metal-matrix composites and metallic glasses. The contours show the specific strength y/r.

Metallic glasses for structural applications

MF Ashby & AL Greer: Scripta Materialia 54 (2006) 321.

(in Viewpoint Set on Mechanical Behavior of Metallic Glasses, edited by TC Hufnagel)

J Schroers et al., Scripta Mater. 57 (2007) 341.

Unachievable shapes for metals?

Hollow, thin, seamless, complex parts ―

[courtesy: Jan Schroers, Yale]

G Kumar, HX Tang & J. Schroers, Nature 457, 868-872 (2009)

Controlling metallic glass moulding on

scales smaller than 100 nm

Pt-based BMG

Nanomoulding with amorphous metals

Surface Replication with BMGs

J. Schroers, Advanced Materials, 21 (2010)

MEMS Applications

A conical spring microactuator with

a long stroke of 200 mm normal to

the substrate. The spring is a 7.6

mm thick film of Pd76Cu7Si17

metallic glass.

T Fukushige, S Hata & A Shimokohbe, J. Microelectro. Syst. 14 (2005) 243.

typical trade-off

between y and Kc

MD Demetriou et al., A damage-tolerant glass, Nature Mater. 10 (2011) 123–128.

AL Greer, Damage tolerance at a price, Nature Mater. 10 (2011) 88–89.

highest known

product of y and Kc

‘damage tolerance’

• The liquid → glass

transition is kinetic

• Therefore there is a

range of glassy states

depending on cooling

rate

fast

slow

Conventionally:

• relaxation (to states of lower energy) ‒ achieved by annealing

• rejuvenation (to states of higher energy ‒ achieved by reheating to liquid

• can a wider range of states be accessed by thermomechanical processing?

• will focus on metallic glassesaccessed by mechanical processing?

potential

energy

binary mixture of LJ particles

minimum energy at ~0.85 Tg

Nature Mater. 12 (2013) 139–144.

Why expand the range of the glassy state?

(in metals)

Relaxation, ultimately to ultrastable states, offers the prospect of:

• great resistance to crystallization

• ultra-high hardness, scratch resistance

• creep resistance

• altered glass-transition behaviour (analogous to melting)

Rejuvenation, to highly unstable states, offers the prospect of:

• fast crystallization

• greater plasticity

• perhaps even tensile ductility

Conventional glasses are

brittle —

— but metallic glasses can

show considerable plasticity:

Methods of cold work

applied to metallic

glasses:

Very high plastic

strains have been

achieved ―

92% rt 93% ra

e = 925

97% rt

shot peening

ECAP

YH Sun, A Concustell & AL Greer: Thermomechanical processing of metallic glasses:

extending the range of the glassy state, Nature Reviews Mater. 1 (2016) 16039.

Cold-rollingStored energy of cold work

Melt-spun ribbons of glassy

Pd77.5Cu6Si16.5

annealed by heating to Tg and

then cooling at 20 K min–1

then cold-rolled

the stored energy is ~4% of the

work done

-- has a maximum value of

1000 J mol–1

stored energy

(stored energy)/(work done)

HS Chen: Stored energy in a cold-rolled metallic glass,

Appl. Phys. Lett. 29 (1976) 328–330.

High-pressure torsion of Zr50Cu40Al10 MG

F Meng, K Tsuchiya, S Il & Y Yokoyama:

Reversible transition of deformation mode by

structural rejuvenation and relaxation in bulk

metallic glass,

Appl. Phys. Lett. 101 (2012) 121914.

2060 J mol–1

this is ~24% of Hmelt

J-C Lee: Calorimetric study of b-relaxation in an amorphous alloy: An experimental

technique for measuring the activation energy for shear transformation,

Intermetallics 44 (2014) 116‒120.

Elastostatic loading of Cu57Zr43 at 85% of Tg for 24 h

Stored energy:

415 J mol–1 at RT

530 J mol–1 at 77 K

AL Greer & YH Sun: Stored energy in metallic glasses due to

strains within the elastic limit, Philos. Mag. 96 (2016) 1643–1663.

The extra energy stored in BMG samples as a result of elastostatic loading

exceeds the mechanical work done on them!

― the loading must induce an endothermic disordering process that draws

heat from the surroundings.

In a glass:

• if elastic strains in a glass are non-affine, then

• then thermal strains should be non-affine also

Uranium has three crystalline polymorphs:

liquidγβα C1132C772C669

is orthorhombic:

(at RT: a = 2.852 Å, b = 5.865 Å, c = 4.945 Å)

b is tetragonal:

(at 720C: a = 10.790 Å, c = 5.656 Å)

is cubic (bcc):

(at 850C: a = 3.538 Å)

Single-crystal -U is strongly

anisotropic.

Temperature dependence of the lattice

parameters of: (1) -U; (2) -U-15

at.% Pu.

Thermal-cycling growth of uranium metal

BRT Frost (ed.), Nuclear Materials (Vols 10A & 10B, Materials Science & Technology),

VCH (1994)

BM Ma, Nuclear Reactor Materials and Applications, Van Nostrand (1983)

Thermal-cycling growth of uranium fuel rods:

Effect of thermal cycling highly oriented fine-grained

α-uranium between 50°C and 500°C.

KL Murty, I Charit: An Introduction to Nuclear Materials, Wiley (2013)

YH Liu, D Wang, K Nakajima, W Zhang, A Hirata, T Nishi, A Inoue & MW Chen:

Characterization of nanoscale mechanical heterogeneity in a metallic glass by dynamic

force microscopy, Phys. Rev. Lett. 106 (2011) 125504.

Energy-dissipation and height-difference maps for a sputter-deposited

Zr55Cu30Ni5Al10 metallic glass

Mapping of

heterogeneity in a

MG

Thermal cycling of MGs

Metallic glass samples are cycled

between room temperature (RT) (or

ethanol at 60‒70°C) and liquid

nitrogen (77 K).

For different glasses, RT and 77 K

are different fractions of Tg.

The cycling is below the

temperature for thermal relaxation.

Glasses in this study:Composition (at.%) Form Tg (K)

Cu46Zr46Al7Gd1 rod, 3 mm diam. 700

La55Ni20Al25 melt-spun ribbon, 40 mm thick 475

La55Ni10Al35 rod, 3 mm diam. 474

Zr62Cu24Fe5Al9 rod, 1.5, 2.0, 2.5 mm diam. 658

SV Ketov et al., Nature 524 (2015) 200–203.

Enthalpies of Relaxation in Metallic Glasses

Increases observed as a result of mechanical treatments

J mol–1

heavily cold-rolled (50–60% red. thickn.) 200–250

(1.5–3% of Hmelt)

Thermal cycling (10 cycles RT – 77 K) 340

Initial yield pressure, Py

cumulative distributions for 40 to 50 indents

median value decreases:

by 3% after 10-min hold at 77 K

by further 17% after ten 1-min

holds

The width (1st to 9th decile) of

the distribution is:

± 7% in the as-cast ribbon

± 15% after all cycles

Thermal cycling softens and introduces greater heterogeneity

SV Ketov et al., Nature 524 (2015) 200–203.

Nanoindentation of La55Ni20Al25 glass ribbon

Comparison of as-cast, partially relaxed (1.0 hr at 400°C) and fully relaxed

(1.5 hr at 400°C):

Plastic strain increases from 1.4% (as-cast) to 5.1% after 10 RT-77K cycles

Similar rejuvenation is possible after partial, but not full relaxation

Compression of bulk Cu46Zr46Al7Gd1

Cuboids, 3 mm high, 1.5×1.5 mm2 cross-section, strain rate ≈ 10–4 s–1

SV Ketov et al., Nature 524 (2015) 200–203.

YH Sun, A Concustell & AL Greer: Thermomechanical processing of metallic glasses:

extending the range of the glassy state, Nature Reviews Mater. 1 (2016) 16039.

Anisotropy

The ideal state of a glass or amorphous

solid is isotropic.

But a glass can be anisotropic:

In this case frozen-in anisotropy comes

from the alignment of the polymer chains

as they flow into the mould cavity.

A Concustell, S Godard-Desmarest, MA Carpenter, N Nishiyama &

AL Greer: Induced elastic anisotropy in a bulk metallic glass

Scripta Mater. 64 (2011) 1091–1094.

RUS studies of a BMG: Pd40Cu30Ni10P20

Approximate sample size: 1.5×2×5 mm3

Fitting of 40 resonant frequencies.

as-cast sample

New tests, focusing on the shear moduli: G4 & G6

― characterize the anisotropy as: A = (G4 – G6)/G4

YH Sun, A Concustell, MA Carpenter, JC Qiao, AW Rayment & AL Greer: Flow-

induced elastic anisotropy of metallic glasses, Acta Mater. 112 (2016) 132–140.

Constant engineering-strain rate tests:

― uniaxial compression at 548 K (0.96 Tg) and 10–3 s−1

― the as-cast glass is isotropic

― cuboid samples cut at various stages show evolving anisotropy

YH Sun, A Concustell, MA Carpenter, JC Qiao, AW Rayment & AL Greer: Flow-

induced elastic anisotropy of metallic glasses, Acta Mater. 112 (2016) 132–140.

Constant engineering-strain rate (at 10–2 s−1) tests:

― uniaxial compression (at 363 K, 0.97 Tg)

― uniaxial tension (at 368 K, 0.99 Tg)

― final values of anisotropy A are shown.

YH Sun, A Concustell, MA Carpenter, JC Qiao, AW Rayment & AL Greer: Flow-

induced elastic anisotropy of metallic glasses, Acta Mater. 112 (2016) 132–140.

YH Sun, A Concustell, MA Carpenter, JC Qiao, AW Rayment & AL Greer: Flow-

induced elastic anisotropy of metallic glasses, Acta Mater. 112 (2016) 132–140.

Effects of annealing and creep in compression:

Anisotropy from

frozen-in anelastic

strain

BMGs

pure metals?

T Masumoto: Mater. Sci. Eng. A 179–180 (1994) 8–16.

Crystals in Pd40Ni40P20 metallic glass

Crystals in Pd40Ni40P20 metallic glass

J Orava & AL Greer: Fast and slow crystal growth kinetics in glass-forming melts

J. Chem. Phys. 140 (2014) 214504.Wang et al. Phys. Rev. B 83 (2011) 014202.

Nascimento et al. J. Chem. Phys. 133 (2010) 174701.

Ashkenazy et al. Acta Mater. 58 (2010) 524. Sun et al. J. Chem. Phys. 31 (2009) 074509.

Tg

Tmax

Cry

sta

l G

row

th R

ate

MD simulations

D Turnbull: Under what conditions can a glass be formed?

Contemp. Phys. 10 (1969) 473‒488.

Turnbull (1969):

Rate of homogeneous crystal

nucleation

Simple scaling analysis

Shows importance of the width

of the labile range between Tg

and Tm

Characterize in terms of the

reduced glass-transition

temperature Trg = Tg/Tm

J Orava & AL Greer: Fast and slow crystal growth kinetics in glass-forming melts

J. Chem. Phys. 140 (2014) 214504.

Turnbull

Trg values

0.40

0.43

0.56

0.660.75

0.64

0.73

0.69

Fokin et al.: Correlation between maximum crystal growth rate and glass transition

temperature of silicate glasses, J. Non-Cryst. Solids 351 (2005) 789–794.

The correlation of Umax and Trg suggested by Fokin et al. for oxide

glass-formers

Higher fragility gives points above the correlation line and vice versa

J Orava & AL Greer: “Fast and slow crystal growth kinetics in glass-forming melts”

J. Chem. Phys. 140 (2014) 214504.

Tgu = Trg ‒ (m/505)

— effectively Trg ‘corrected’ for fragility m

meanwhile — a group at Glassimetal Technology Inc. and the California

Institute of Technology was working on:

Composition dependence of glass-forming ability in

the Ni-Cr-Nb-P-B system

The glass-forming ability (GFA) is characterized by the maximum rod

diameter dcr that can be cast fully glassy.

dcr shows a strong (exponential) dependence on composition

dcr is maximum at eutectic compositions

JH Na, MD Demetriou, M Floyd, A Hoff, GR Garrett & WL Johnson:

Compositional landscape for glass formation in metal alloys,

PNAS 111 (2014) 9031–9036.

JH Na, MD Demetriou, M Floyd, A Hoff, GR Garrett & WL Johnson:

Compositional landscape for glass formation in metal alloys,

PNAS 111 (2014) 9031–9036.

JH Na, MD Demetriou, M Floyd, A Hoff,

GR Garrett, WL Johnson: Compositional

landscape for glass formation in metal

alloys, PNAS 111 (2014) 9031–9036.

GFA is correlated with both Trg

and m

Trg and m are independent

parameters

GFA is exceptionally well

correlated with a single

parameter:

Trg – (m/390) (in PNAS)

— and with more data revised to:

Trg – (m/520)

JH Na, MD Demetriou, M Floyd, A Hoff,

GR Garrett, WL Johnson: Compositional

landscape for glass formation in metal

alloys, PNAS 111 (2014) 9031–9036.

GFA is correlated with both Trg

and m

Trg and m are independent

parameters

GFA is exceptionally well

correlated with a single

parameter:

Trg – (m/390) (in PNAS)

— and with more data revised to:

Trg – (m/520)

It seems that GFA can be accurately predicted from just two

parameters:

• reduced glass-transition temperature Trg

• liquid fragility m

— but is this effect through nucleation or growth, or both?

Tg

Tmax

Cry

sta

l G

row

th R

ate

MD simulations

J Orava & AL Greer: “Fast and slow crystal growth kinetics in glass-forming melts”

J. Chem. Phys. 140 (2014) 214504.

The growth rate for chalcogenide GST lies between pure metals and

the glass-forming Cu50Zr50.

GST lies:

between pure

metals and

glass-forming

alloys

Rewritable optical discs are a successful technology

but the key goal for the future of chalcogenide phase-change media is —

random-access memory (RAM)

• the leading manufactures and developers are:

Ovonyx Ovonic Unified Memory (OUM) (“ECD Ovonics has invented a basic phase-

change solid-state storage technology, which is now being developed by joint venture

Ovonyx, Inc.”) – founded by S. R. Ovshinsky

Numonyx (2007 - STMicroelectronics + Intel “to better face increasingly stiff competition

in the Flash memory market” – working on RAM cells as well)

Samsung “09/22/2009, LONDON - South Korean electronics giant Samsung Electronics

Co. Ltd. has announced that it has begun production of a 512-Mbit phase-change

random access memory and is aiming it at mobile phone handsets and other battery-

operated applications.”

- others on the market: Panasonic, IBM, LETI...

• heating by electric current through the chalcogenide

Time

Te

mpe

ratu

re

Ta

T

T

m

x

AmorphizingRESET Pulse

Crystallizing(SET) Pulse

t1

t2

Programming of memory devices (schematic)

top electrode

polyc. GST

act. GST

he

ate

r

ins

ula

tor

ins

ula

tor

bottom electr.

typical heater

Resistance vs current for a phase-change memory device

Multi-state electrical phase-change memory“Threshold switching”

SR Ovshinsky: “Optical

cognitive information

processing — a new field”

Jpn. J. Appl. Phys. 43 (7B)

(2004) 4695.

14 August 2014:

Nature 512 (2014) 177–182

• formation of pure glassy Mo, Ta, V, W (all bcc) by liquid quenching

• e.g. for Ta, the cooling rate is as high as 1014 K s–1 at 4200 K

• failed to make fcc metals glassy (Ag, Al, Au, Cu, Ir, Pd, Rh)

• the glass formation is by suppression of growth

• the glasses show clear structural relaxation at RT (XRD)

• W glass is unstable at RT.

L Zhong, J Wang, H Sheng, Z Zhang & SX Mao: Formation of monatomic

metallic glasses through ultrafast liquid quenching, Nature 512 (2014) 177–182.

L Zhong, J Wang, H Sheng, Z Zhang & SX Mao: Formation of monatomic

metallic glasses through ultrafast liquid quenching, Nature 512 (2014) 177–182.

Ta

Heating by 4 ns

electric pulse at

0.5–3 V.

The fully glassy

region is 20 nm

long and 15 nm

thick.

L Zhong, J Wang, H Sheng, Z Zhang & SX Mao

Formation of monatomic metallic glasses through ultrafast liquid quenching

Nature 512 (2014) 177–182.

Controlled gradual crystallization of glassy Ta

Reversible vitrification–crystallization

potential

energy

binary mixture of LJ particles

minimum energy at ~0.85 Tg

Nature Mater. 12 (2013) 139–144.

Relative enthalpies based on measured data for

Zr52.5Cu17.9Ni14.6Al10Ti5 BMG:

S.C. Glade, R. Busch, D.S. Lee, W.L. Johnson, R.K. Wunderlich and H.J. Fecht:

Thermodynamics of Cu47Ti34Zr11Ni8, Zr52.5Cu17.9Ni14.6Al10Ti5 and Zr57Cu15.4Ni12.6Al10Nb5

bulk metallic glass forming alloys, J. Appl. Phys. 87 (2000) 7242–7248.

20 K min–1

Relative enthalpies based on measured

data for Zr52.5Cu17.9Ni14.6Al10Ti5 BMG

20 K min–1

Relative enthalpies based on measured

data for Zr52.5Cu17.9Ni14.6Al10Ti5 BMG

Conclusions

• metallic glasses form mainly at deep eutectic compositions

• structure is based on dense packing

• glass-forming ability is correlated with Trg and liquid fragility m

• can plastically deform at room temperature

• can induce anisotropy

Energy:

• elastostatic loading induces endothermic disordering

• rejuvenation is possible (by irradiation, ‘elastic’/plastic deformation)

• show a wide range of states (energy ≈ Hm)

Thermal cycling:

• stored energy, softening and improved plasticity

Crystallization:

• much to understand; possible interest in fast crystallization

Record-breaking mechanical properties:

• ‘damage tolerance’ (y × Kc)